Movement disorders are often caused by chronic neurodegenerative diseases such as Parkinson's Disease (“PD”) and Essential Tremor (“ET”). Both of these conditions are currently incurable and cause unintentional muscle movements or human tremors—uncontrollable rhythmic oscillatory movements of the human body. In many cases human tremors can be severe enough to cause a significant degradation in quality of life, interfering with daily activities/tasks such as eating, drinking, or writing.
Patients with movement disorders are typically diagnosed in a clinic using scales such as the Fahn-Tolosa-Marin Tremor Rating Scale for ET or the Unified Parkinson Disease (UPDRS) rating scale for PD. Both of these scales require a trained neurologist to complete and often rely on subjective assessments that occur over a brief period of time in the practitioner's office. Symptom severity at home is typically evaluated from the patient's self-reporting, which is also highly subjective and prone to error. Some devices have been used to track lower extremity freezing, but require bulky and obtrusive sensors that a user must wear. This creates significant challenges when diagnosing, developing and evaluating long-term treatments or interventions for these diseases.